Leipheimer, the Omega Pharma-Quickstep rider based in Santa Rosa, Calif., began the day in fourth place - 8 seconds back. He was fourth in the stage, 26 seconds behind Sutherland.
The second-year race will end Sunday with a 9.5-mile time trial in Denver.
Sutherland, who competes for U.S.-based UnitedHealthcare, completed the 102.8-mile stage from Golden, the last mountain stage of the weeklong race, in 4 hours, 6 minutes, 12 seconds for his second win of the season.
Former race leader Christian Vande Velde of Garmin-Sharp and Lemont, Ill., dropped to second overall.
Tejay van Garderen, the Garmin-Sharp rider from Bozeman, Mont., who has twice led the race via tiebreaker, faded in the waning miles and finished 11th. Van Garderen was third overall, trailing Leipheimer by 21 seconds.
Fabio Aru of Italy was second in the stage, 20 seconds behind Sutherland.
(Copyright 2012 The Associated Press. All rights reserved.)